Scavenging pump

ABSTRACT

A scavenging pump is utilized to draw oils from a catch tank that collects the oils supplied to components to an oil pan that reserves therein the oils. The scavenging pump includes gears to draw the oils, and a housing that stores therein the gears. An oil receiving portion capable of receiving the oils injected from the exterior is formed in an outer circumferential surface of the housing, and an oil introducing hole that introduces the oils injected to the oil receiving portion into the interior is opened at a position continuous from a lower part of the oil receiving portion and facing the gears.

FIELD OF THE INVENTION

The present disclosure relates to a scavenging pump that draws oils from a catch tank which collects the oils supplied to components to an oil pan which reserves therein the oils.

BACKGROUND

Some vehicles are provided with components, such as a turbocharger. Such components are allowed to operate and are cooled by lubrication oils that circulate within a vehicle. Oils that pass through a component are collected by a catch tank, and are returned to an oil pan from the catch tank. At this time, when the catch tank is located at a lower site than that of the catch tank, oils are drawn from the catch tank to the oil pan using a scavenging pump. JP 2019-78190 A discloses a conventional technology related to such a scavenging pump.

JP 2019-78190 A describes the features of a scavenging pump by a comparison with a feed pump for circulating oils. One of such features is that, although a feed pump carries substantially oils only, a scavenging pump carries not only oils but also air.

SUMMARY OF THE INVENTION

For example, immediately after the start-up of a vehicle, sufficient oils are not circulated in a scavenging pump, and oils are hardly filled therein in some cases. Even if the scavenging pump is operated in such a state, a large amount of air is present between gears for drawing the oils. When the oils filled in the scavenging pump are insufficient, a sealing performance decreases, making it difficult for such a pump to draw the sufficient amount of oil. Hence, there is a leeway for an improvement in view of an efficient circulation of oils.

An objective of the present disclosure is to provide a scavenging pump that can efficiently circulate oils.

According to the present disclosure, a scavenging pump is provided which is utilized to draw oils from a catch tank that collects the oils supplied to a component to an oil pan that reserves therein the oils, and which includes:

-   -   gears to draw the oils; and     -   a housing that stores therein the gears,     -   in which an oil receiving portion capable of receiving the oils         injected from an exterior is formed in an outer circumferential         surface of the housing, and an oil introducing hole that         introduces the oils injected to the oil receiving portion into         an interior is opened at a position continuous from a lower part         of the oil receiving portion and facing the gears.

According to the present disclosure, a scavenging pump that can efficiently circulate oils is provided.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exemplary diagram of an oil circulating device that utilizes a scavenging pump according to an embodiment of the present disclosure;

FIG. 2 is a perspective view of the scavenging pump illustrated in FIG. 1;

FIG. 3 is an exploded view of the scavenging pump illustrated in FIG. 2;

FIG. 4A is a diagram for describing an action of a scavenging pump according to a comparative example; and

FIG. 4B is a diagram for describing an action of the scavenging pump according to the embodiment.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Embodiments of the present disclosure will be described below with reference to the accompanying figures. Note that “Up” and “Dn” in the figure indicate an upper side and a down side, respectively.

[Embodiment]

With reference to FIG. 1, for example, a vehicle is provided with an oil circulating device 10 for circulating oils. A scavenging pump 20 according to the present disclosure forms a part of the oil circulating device 10.

The oil circulating device 10 includes an oil pan 11 that reserves therein oils Oi, a feed pump 12 that can draw the oils Oi from the oil pan 11, a catch tank 14 that collects the oils Oi which are fed to a turbocharger 13 from the feed pump 12, and which cool the turbocharger 13, a scavenging pump 20 that draws the oils Oi from the catch tank 14 to the oil pan 11, and a nozzle 16 that can inject the oils Oi to the scavenging pump 20.

The flow channel of the oil circulating device 10 is branched in order to lubricate other various components to operate and to cool those in addition to the turbocharger 13. The oils Oi that pass through the other components are also returned to the oil pan 11.

In this example, the components which are lubricated by the oils Oi to operate and are cooled are, in addition to the engine, the turbocharger 13, a supercharger, etc. In this embodiment, a description will be given of a case in which the example component which is lubricated by the oils to operate and which is cooled is the turbocharger 13. The turbocharger 13 will be also referred to as a “component 13”.

With reference to FIG. 2, the nozzle 16 is provided so as to face the scavenging pump 20. When, for example, the scavenging pump 20 is operated, the oils Oi are injected to the scavenging pump 20 from the nozzle 16. The reason will be described later.

With reference to also FIG. 3, the scavenging pump 20 includes an inner rotor 22 provided so as to be rotatable, an outer rotor 23 which surrounds the inner rotor 22, and which rotates together with the rotation of the inner rotor 22, and a housing 30 that stores therein those rotors.

The housing 30 includes a main body 31 that stores therein the inner rotor 22 and the outer rotor 23, and a cover 32 that is laid over on the main body 31.

The main body 31 is provided with an inlet hole 31 a that is opened so as to let the oils to enter from the exterior, an inlet port 31 b that guides the oils from the inlet hole 31 a to the inner rotor 22 and to the outer rotor 23, a discharge port 31 c to which the oils guided from the inlet port 31 b is delivered, and a discharge hole 31 d that is opened so as to discharge, to the exterior, the oils delivered to the discharge port 31 c.

An oil receiving portion 32 b that can receive the oils injected from the nozzle 16 is formed in the outer circumferential surface of the cover 32 so as to be concaved toward the side face of the inner rotor 22 and that of the outer rotor 23 relative to a general surface 32 a. Moreover, an oil introducing hole 32 c that is continuous from the lower part of the oil receiving portion 32 b is opened at a position that overlaps a boundary between the inner rotor 22 and the outer rotor 23.

The general surface 32 a and the oil receiving portion 32 b are connected by a guide portion 32 d that guides the oils Oi to the oil introducing hole 32 c. The guide portion 32 d is continuously formed along the outer circumference of the oil receiving portion 32 b, and the edge of the oil introducing hole 32 c.

The oil receiving portion 32 b is formed in such a way that the width gradually decreases toward the oil introducing hole 32 c formed at the down side. Moreover, the length of the oil receiving portion 32 b in the vertical direction is longer than the diameter of the oil introducing hole 32 c formed in a cylindrical shape. The area of the oil receiving portion 32 b is larger than the area of the oil introducing hole 32 c.

The oil introducing hole 32 c is opened so as to introduce the injected oils Oi to the oil receiving portion 32 b into the interior of the housing 30. The oil introducing hole 32 c is formed at a position that overlaps a boundary between the inner rotor 22 and the outer rotor 23.

With reference to FIG. 4B, for example, the oil introducing hole 32 c increases the diameter toward the inner circumferential surface from the outer circumferential surface. That is, the diameter of the oil introducing hole 32 c is large at the inner-circumferential-surface side relative to the outer-circumferential side.

Note that the position in which the oil introducing hole 32 c is formed may be located above the boundary between the inner rotor 22 and the outer rotor 23.

Moreover, the oil introducing hole 32 c may have the uniform diameter from the outer-circumferential-surface side to the inner-circumferential-surface side. Furthermore, the oil introducing hole 32 c may have the uniform diameter from the inner-circumferential-surface side to the outer-circumferential-surface side, and inclined downwardly toward the inner circumferential surface.

An oil retaining portion 32 e that retains therein the oils Oi is provided under the oil introducing hole 32 together with the guide portion 32 d and along the lower part of the guide portion 32 d. The oil retaining portion 32 e is formed in a substantially semi-circular shape along the edge of a lower-half circumference of the oil guide portion 32 d. It is preferable that the upper surface of the oil retaining portion 32 e should be located higher than the lower edge of the oil introducing hole 32 c at the outer-surface side.

Note that the oil retaining portion 32 e may be formed integrally with the general surface 32 a, not as a separate component.

A bar-shape shaft member passes completely through the center of the inner rotor 22. The shaft member is coupled to, for example, the crankshaft of an engine. In this case, when the engine runs, the crankshaft rotates, and the inner rotor 22 also rotates. The outer rotor 23 placed at the outer-circumference side of the inner rotor 22 rotates when the inner rotor 22 rotates.

Note that the inner rotor 22 and the outer rotor 23 are gears that draw the oils by rotation. In the following description, the inner rotor 22 and the outer rotor 23 may be collectively referred to as “gears 22 and 23”.

With reference to FIG. 1 and FIG. 3, when the gears 22 and 23 rotate, the oils Oi are drawn from the catch tank 14. The drawn oil Oi flow to the inlet port 31 b from the inlet hole 31 a. The oils Oi are suctioned in a space surrounded by the inner rotor 22 and the outer rotor 23 from the inlet port 31 b. The suctioned oils Oi are discharged to the discharge port 31 c since the space surrounded by the inner rotor 22 and the outer rotor 23 becomes small. The discharged oils Oi to the discharge port 31 c are discharged to the exterior of the housing 30 from the discharge hole 31 d, and are returned to the oil pan 11.

Meanwhile, immediately after the vehicle starts, the sufficient oils Oi are not circulated yet, and the substantially all oils Oi in the scavenging pump 20 are fallen, and thus the sealing performance of the scavenging pump 20 is insufficient in some cases. Even if the scavenging pump 20 is operated from such a state, a large amount of air is present between the inner rotor 22 and the outer rotor 23. Since the force that draws the oils Oi is weak when the sealing performance between the inner rotor 22 and the outer rotor 23 is low, and thus it is difficult to circulate the sufficient amount of the oils Oi. Hence, the oils Oi are injected from the nozzle 16, and the oils Oi are supplied to the interior of the housing 30. By supplying the injected oils Oi to the interior of the housing 30, the sealing performance between the inner rotor 22 and the outer rotor 23 can be enhanced. Accordingly, the sufficient oils Oi reserved in the catch tank 14 can be drawn. That is, the injected oils Oi from the nozzle 16 serve as priming oils.

The nozzle 16 starts injecting the oils immediately after the engine runs, or with a time lag that is several seconds. As far as the engine keeps running, the injection of the oils Oi from the nozzle 16 is maintained. At this time, the pressure of the oils injected from the nozzle 16 changes in accordance with the engine revolution speed. When the engine revolution speed is fast, the oils are injected at high pressure.

The scavenging pump 20 as described above can be summarized as follows.

The scavenging pump 20 is utilized to draw the oils Oi from the catch tank 14 that collects the oils Oi supplied to the component 13 to the oil pan 11 that reserves therein the oils Oi. Moreover, the scavenging pump 20 includes the gears 22 and 23 to draw the oils Oi, and the housing 30 that stores therein these gears 22 and 23. The housing 30 has the oil receiving portion 32 b which can receive the oils Oi injected from the exterior and which is formed in the outer circumferential surface, and has the oil introducing hole 32 c which is continuous from the lower part of the oil receiving portion 32 b, is to introduce the injected oils Oi to the oil receiving portion 32 b to the interior and is opened at a position facing the gears 22 and 23.

Since the oil introducing hole 32 c is opened in the housing 30, the injected oils Oi toward the housing 30 from the exterior can be introduced therein. Some oils Oi introduced in the housing 30 flow through between the gears 22 and 23, and thus the sealing performance between the gears 22 and 23 is enhanced. This makes it possible for the scavenging pump to efficiently draw the oils Oi. That is, the scavenging pump 20 can efficiently circulate the oils Oi.

The reason why the oil receiving portion 32 b is formed in the housing 30 will now be described.

With reference to FIG. 4A, the inventors of the present disclosure first created a scavenging pump 120 that had only an oil introducing hole 132 c formed in a housing 130. Such a scavenging pump 120 was able to efficiently circulate oils, but there is a leeway for an improvement regarding the efficient oil circulation. Based on keen examinations, the inventors of the present disclosure found that since the oils Oi injected from a nozzle 116 is directly injected to gears 122 and 123, the gears 122 and 123 are slightly displaced, and the flow volume for drawing the oils decreases. Moreover, even if the oils Oi do not directly contact the gears 122 and 123, the discharging side flow channel of the discharge hole 31 d is clogged by the pressure of the injected oils Oi, and thus it becomes a state in which the oils Oi are stuck. Consequently, the flow volume for drawing the oils decreases.

With reference to FIG. 4B, the inventors of the present disclosure designed to form, in the outer circumferential surface of the housing 30, the oil receiving portion 32 b that can receive the injected oils Oi from the nozzle 16, and to form, continuously from the lower part of the oil receiving portion 32 b, the oil introducing hole 32 c that introduces the injected oils Oi to the oil receiving portion 32 b into the interior of the housing 30. The oils Oi are injected to the oil receiving portion 32 b from the nozzle 16, flow through the oil receiving portion 32 b, and reach the oil introducing hole 32 c. The oils that have reached the oil introducing hole 32 c pass through the oil introducing hole 32 c, and reach the interior of the housing 30. Accordingly, the oils Oi gradually flow into the interior of the housing 30. Such a scavenging pump 20 was able to increase the flow volume of the circulated oils in comparison with the scavenging pump 120 (_(see) FIG. 4A) according to a comparative example. That is, the scavenging pump 20 can further efficiently circulate the oils Oi.

Moreover, the guide portion 32 d that guides the oils Oi to the oil introducing hole 32 c is formed along the edge of the oil introducing hole 32 c at the outer-circumferential-surface side. The guide portion 32 d can guide the oils Oi to the oil introducing hole 32 c. Hence, the more oils Oi injected to the oil receiving portion 32 b can be guided to the interior of the housing 30, thereby ensuring the sealing performance between the gears 22 and 23. This causes the oils Oi to be further efficiently circulated.

With reference to FIG. 3, furthermore, the area of the oil receiving portion 32 b is larger than the area of the oil introducing hole 32 c. The injected oils can be further surely received by the oil receiving portion 32 b, and the direct injection of the oils to the oil introducing hole 32 c is suppressed. This results in a further efficient circulation of the oils Oi.

With reference to FIG. 4B, the housing 30 has the oil retaining portion 32 e which can retain the oils together with the guide portion 32 at the lower part of the oil introducing hole 32 c. Since the oil retaining portion 32 e is formed, the oils that flows downwardly through the oil receiving portion 32 b can be further surely introduced into the oil introducing hole 32 c. Note that the guide portion 32 d may be formed in a planar shape, or may be inclined downwardly toward the oil introducing hole 32 c.

Moreover, the oil introducing hole 32 c increases the diameter toward the inner circumferential surface side from the outer circumferential surface. When, for example, a vehicle stops at a sloping road, the scavenging pump 10 may be inclined relative to the horizontal axis. According to the above-described structure, even if the scavenging pump 10 is inclined, the oils that contact the oil receiving portion 32 b can be surely introduced into the interior of the pump.

With reference to FIG. 3, the oil receiving portion 32 b is formed so as to gradually decreases the width toward the oil introducing hole 32 c. This enables the oil receiving portion 32 b to receive the further more oils, and further surely causes the received oils to be guided to the oil introducing hole 32 c. Hence, the oils Oi can be further efficiently circulated.

Note that, in general, the oil pan 11 (see FIG. 1) is always filled with the oils that are equal to or greater than a certain amount. Hence, according to the feed pump 12 that draws the oils from the oil pan 11, a certain level of sealing performance between the gears is maintained. That is, under a predetermined condition, the problem such that the sealing performance is low between the gears 22 and 23 like the scavenging pump 20 is not likely to occur at all. In this point, the feed pump 12 and the scavenging pump 20 remarkably differ from each other.

Although the scavenging pump according to the present disclosure has been described with reference to an example case applied to a vehicle, it can be applied to conveyances other than vehicles, and construction machineries, etc., and the present disclosure is not limited to such forms. Moreover, although the scavenging pump that is an internal-gear pump has been described as an example, internal-contact gear pump to an example, the present disclosure is applicable to an external-contact gear pump.

That is, as far as the actions and advantageous effects of the present disclosure are accomplishable, the present disclosure is not limited to the embodiments.

INDUSTRIAL APPLICABILITY

The scavenging pump according to the present disclosure is suitable to draw oils for cooling a vehicle to an oil pan. 

1. A scavenging pump utilized to draw oils from a catch tank that collects the oils supplied to a component to an oil pan that reserves therein the oils, and comprising: gears to draw the oils; and a housing that stores therein the gears, wherein an oil receiving portion capable of receiving the oils injected from an exterior is formed in an outer circumferential surface of the housing, and an oil introducing hole that introduces the oils injected to the oil receiving portion into an interior is opened at a position continuous from a lower part of the oil receiving portion and facing the gears.
 2. The scavenging pump according to claim 1, wherein a guide portion that guides the oils to the oil introducing hole is formed along an edge of the oil introducing hole at an outer-circumferential-surface side thereof.
 3. The scavenging pump according to claim 1, wherein an area of the oil receiving portion is larger than an area of the oil introducing hole.
 4. The scavenging pump according to claim 2, wherein the housing comprises an oil retaining portion which is capable of retaining the oils together with the guide portion at a circumferential edge of the oil introducing hole.
 5. The scavenging pump according to claim 1, wherein the oil introducing hole increases a diameter from an outer circumferential surface to an inner circumferential surface.
 6. The scavenging pump according to claim 1, wherein the oil receiving portion gradually reduces a width toward the oil introducing hole.
 7. The scavenging pump according to claim 1, wherein: a guide portion that guides the oils to the oil introducing hole is formed along an edge of the oil introducing hole at an outer-circumferential-surface side thereof; and an area of the oil receiving portion is larger than an area of the oil introducing hole.
 8. The scavenging pump according to claim 1, wherein: a guide portion that guides the oils to the oil introducing hole is formed along an edge of the oil introducing hole at an outer-circumferential-surface side thereof; and the oil introducing hole increases a diameter from an outer circumferential surface to an inner circumferential surface.
 9. The scavenging pump according to claim 1, wherein: an area of the oil receiving portion is larger than an area of the oil introducing hole; and the oil introducing hole increases a diameter from an outer circumferential surface to an inner circumferential surface.
 10. The scavenging pump according to claim 1, wherein: the housing comprises an oil retaining portion which is capable of retaining the oils together with the guide portion at a circumferential edge of the oil introducing hole; and the oil introducing hole increases a diameter from an outer circumferential surface to an inner circumferential surface.
 11. The scavenging pump according to claim 1, wherein: a guide portion that guides the oils to the oil introducing hole is formed along an edge of the oil introducing hole at an outer-circumferential-surface side thereof; and the oil receiving portion gradually reduces a width toward the oil introducing hole.
 12. The scavenging pump according to claim 1, wherein: an area of the oil receiving portion is larger than an area of the oil introducing hole; and the oil receiving portion gradually reduces a width toward the oil introducing hole.
 13. The scavenging pump according to claim 1, wherein: the housing comprises an oil retaining portion which is capable of retaining the oils together with the guide portion at a circumferential edge of the oil introducing hole; and the oil receiving portion gradually reduces a width toward the oil introducing hole.
 14. The scavenging pump according to claim 1, wherein: the oil introducing hole increases a diameter from an outer circumferential surface to an inner circumferential surface; and the oil receiving portion gradually reduces a width toward the oil introducing hole. 